Jeep Strokers

Hello, all.

I like to get some sage feedback on my plan for a first-time stroker build. I have a 2001 XJ that I use to tool around my land in the mountains and is also my DD. No crawling or serious recreational off-roading. My goals are more grunt and top end to roll my 31x10.50s a little easier on the highway and help out in the occasional logging road mud rut. Reliability is a priority.


Planned ingredients:

2001 XJ 4.0 block (ATK Reman motor from NAPA I installed about 30,000 miles ago)
Head from same motor - stock (will likely do a DIY gasket match)
Thinner head gasket to keep compression in pump gas range (target 9:25:1 or somewhere thereabouts)
4.0 Connecting Rods
258 Lightweight Crank with the longer snout
4.2 hypereutectic pistons
Stock 4.0 cam (new lifters, springs, and pushrods)

Questions:

Is it recommended to overbore? If so, by how much?
Should I go with forged pistons instead? (I'm doing the build because my old pistons cracked at about 30k miles)
The motor has relatively few miles on it since I bought it (remanufactured). Should I get the block and head shaved a bit?
Will a stock cam be the best option for DD and reliability, or do I need more duration etc.?

Thanks, folks.

You'll need shorter ~1.380" compression height hypereutectic stroker pistons to go with the 258 crank & 4.0 rods. Keep in mind that you'll need a 10mm thick spacer in front of the harmonic balancer if you use a longer snout crank.

You'll need a longer duration cam if you're looking for more top end. Russ Pottenger can supply you the necessary parts so contact him for advice and pricing.

Thanks. I'll send Russ a message.

Is an overbore recommended, or will the standard bore work fine?

Plan for an overbore but you will have to check your block when it's torn down if you want to know for sure

Since there is only 30k miles on a rebuild, you may get away without serious machine work. Again, no way to guess until you get it apart.

A brand new engine will have structural stresses in the metallurgy. As the engine goes through numerous thermal cycles, some of the stressed molecules "snap" and relax. Over time, there is distortion of the metal itself. Rebuilding an engine with proper machine work brings everything back to true. The rebuilt engine may last longer than the new engine just because of that fact alone.

Thanks for the advice.

I think a deck and head check is in order to make sure it's all trued up.

I'm running Banks Power headers on the stock 4.0 right now. Any other easy mods (other than port matching etc.) that you all would recommend to help it breathe a little better? I know there's a bit of a debate on going up to the 62mm TB.

BlueRidgeXJ wrote: ↑April 14th, 2025, 8:34 pm I know there's a bit of a debate on going up to the 62mm TB.

There's no debate. A 62mm TB is the bare minimum you need on a mild 4.6L stroker and you could easily go bigger.